1. Field of the Invention
The present invention relates primarily to a multi-layered electrically activated coating or appliqué applied to devices or substrates, particularly electronic and circuit components which can be automatically activated, or activated at the option of the user, to release an oxidizing agent to decontaminate the surface of the substrate or device while not being destructive of the underlying substrate or the surrounding environment. In particular, the oxidizing agent is effective in deactivating or substantially reducing the effectiveness of certain chemically and biologically active agents that it comes in contact with. The coating or cell can also be readily reactivated after activation and depletion. The invention also provides a multi-layered electrolytic cell which, even in the absence of aqueous media, can release controlled amounts of a decontaminating agent into an enclosed space.
2. Description of the Related Art
The surfaces of devices, and particularly electronics enclosed within or behind a protecting structure such as a control panel or a enclosing case, are particularly difficult to decontaminate once exposed to contaminating or toxic chemical or biological agents. The difficulties arise in part from the inability to gain access to the enclosed space and, even where access can be accomplished, from the need to introduce decontaminating agents into small spaces in or behind the devices or components thereof. Still further, many decontaminating agents are delivered as aqueous solutions. The aqueous solvent can also be detrimental to the functionality of the device being decontaminated, causing the electrical components to short circuit and metal components to oxidize (rust).
There are numerous examples of decontamination agents that can be applied to a contaminated surface after the surface has been exposed to a contaminant. For example, U.S. Pat. No. 6,566,574 covers a composition including a solubilizing agent for the contaminant, particularly cationic surfactants, and at least one reactive compound that attacks or neutralizes the contaminant. Published U.S. Application 2004/0045479, and its parent U.S. Pat. No. 6,057,488, discloses the use of finely divided metal oxides of hydroxides, which are applied to contaminated surfaces. There are also examples of coatings of various different compositions. For example, U.S. Application No. 2004/0109853 discloses a coating containing a phosphoric acid triestester hydrolase. In addition, U.S. Pat. No. 6,566,574 to Tadros et al. discloses materials delivered as foams, sprays, liquids, fogs or aerosols to neutralize chemical or biological agents already contaminating a surface.
Treatments using resins containing decontamination agents have been described. U.S. Pat. No. 6,562,885 to Moorehead et al. is directed to a substance capable of devitalizing hazardous biological agents and deactivating hazardous chemical agents comprising an activated anion exchange resin having a particle size in the range of about 0.1-300 microns, the resin particles being iodinated by exposure to a sufficient amount of an iodine-substance absorbable by the anion exchange. The resin particles absorb the iodine-substance converting the resin particles into activated resin particles. The iodine-substance is selected from the group consisting of I2 (i.e., diatomic iodine), and polyiodide ions having a valence of −1. The activated resin particles are placed into contact with the biological or chemical agent after contamination as a dry aerosol, by dust coating, or by admixing the particles with a carrier to form a coating. The activated resin particles can also be applied to the surface of an object, providing a continuously active coating (active once applied; can not be activated at-will or when the contamination is present).
U.S. Pat. No. 5,639,452 to Messier discloses a disinfectant substance comprising an iodine impregnated ion exchange resin which is a demand-type broad spectrum resin-polyiodide disinfectant useful in sterilizing fluids, and particularly a polyiodide that leaves behind nondetectable or otherwise acceptable residual diatomic iodine in treated fluids. U.S. Pat. No. 5,431,908 to Lund also teaches a method of preparing halide-impregnated ion exchange resins useful in purifying fluids such as water.
Polymeric decontaminations systems have also been described. U.S. Pat. No. 5,236,703 is directed to a polymeric substrate, such as rubber or latex, which incorporates povidone-iodine which acts as a controlled release biologically active agent. U.S. Pat. No. 5,154,920 discloses a liquid disinfectant composition which can be used to coat surfaces of a substrate with a polymeric film to impart prolonged germicidal properties to the coated surface by inclusion of phenols, or quaternary ammonium salts. U.S. Pat. No. 4,798,870 is directed to hydrohalide-polyhalides or quaternary halide-perhalide salts which are bound to polymeric surfaces, such as a fabric or polymer film, using a vinylpyridine as a binding agent. Disinfectant patches have been constructed using conventional technology in which nano-silver (nano-Ag) particles or quaternary ammonium compounds are included in the absorbent gauze dressing.
Electrochemically-generated oxidants such as peroxides, hypohalites, and high valent halogens (halogen gases and halo-oxides) can also be effective decontamination agents. The industrial production of chlorine bleach (NaOCl) by the electrolysis of brine, for example, employs electrolytic formation of chlorinated disinfectants. These techniques typically use aqueous solutions, usually held within a container, that build up electrochemically-generated oxidants either on or in an object placed in the solution, as described in U.S. Pat. Nos. 5,250,160 and 6,555,055. They have also been used to purify other bodies of liquids such as streams or pools of water, as described in U.S. Pat. No. 7,033,509.
However, each of these references suffers from one or more of the following disadvantages: the active ingredients are external and must be placed in physical contact with the contaminated surface of the object in order to decontaminate it; the composition or resin is active once applied but can not be activated on demand; the active ingredients are difficult to regenerate if depleted; the systems or coatings used for decontamination are inflexible; the oxidizing agent generated is too acidic or too strong an oxidant to be used in many types of applications (e.g. chlorine or chloride), including the disinfection of electronics and sensitive surfaces such as human skin; the solvents or carriers used to deposit, dissolve, or suspend the active ingredients are detrimental to the functionality of the object or device being treated; the addition of liquid disinfectants requires an additional step in the treatment protocol; the decontaminating surfaces are prone to fouling (i.e. buildup of an overlayer of biological or other types of debris) which leads to a loss of activity; inclusion of active halogens in a dressing is problematic owing to the unstable highly reactive state of the active halogen or halogenated compound; activation of the system is hazardous to the environment or to human health or safety; or the technique requires an enclosed space filled with water or aqueous media, heavy or bulky equipment, or is too costly for remote or application.